NETWORK ADDRESS TRANSLATION CONTROL PROGRAM, NETWORK ADDRESS TRANSLATION CONTROLLER, AND NETWORK ADDRESS TRANSLATOR CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide techniques for suppressing an decrease in entry utilization efficiency and an increase in inquiry frequency, thereby achieving an environment for comfortable communication through a network address translator (NAT) apparatus.;SOLUTION: A domain name system (DNS) server 11 stores in a private address cache 11b a private address obtained by inquiry by means of a fully qualified domain name (FQDN) from a DNS server 21 of a LAN 20. An entry preparation request for allocating a global address to the private address for the NAT apparatus 30 is made by using the private address if it is stored in the private address cache 11b, and if it is not stored in the cache, the request is made by acquiring it by inquiry to the DNS server 21. Thus, the inquiry frequency for acquiring the private address can be reduced without maintaining the entry on the side of the NAT apparatus 30 after end of communication. Since it is not necessary to maintain the entry after end of communication, a decrease in entry utilization efficiency can be suppressed.;COPYRIGHT: (C)2010,JPO&INPIT